1. Field of the Invention
The present invention relates to a driving evaluation apparatus, a driving evaluation program and a driving evaluation method for evaluating a result of driving of a vehicle (fuel consumption, vehicle speed etc.) in certain driving interval on the basis of driving data of the driving interval. More particularly, the invention relates to a driving evaluation apparatus, a driving evaluation program and a driving evaluation method capable of properly evaluating a driving result while considering situations of various driving roads that cannot be improved by driving skills.
2. Related Art
Because of increasing environment awareness and for the purpose of reducing fuel cost in transportation business, an information system for assisting a driver to learn a driving skill to efficiently drive is in demand. In such a system, a driving evaluation method of evaluating driving from the viewpoint of fuel consumption rate (specific fuel consumption) on the basis of driving data is necessary.
For example, it is also possible to determine an evaluation value, by calculating fuel consumption rate of one day by dividing travel distance in driving data of one day by total fuel consumption amount and checking the fuel consumption rate with a fuel consumption statistic distribution or the like. In such a method, however, there is a problem such that the driver forgets a problem in his/her driving, so that effective assistance cannot be given. It is therefore important to evaluate a driving result in a time interval from a past relative short time to the present time point by using only interval driving data as driving data in the interval and immediately provide the evaluation result to the driver.
The situations (driving environments) of a driving road such as continuation of steep slopes and curves, traffic jam, and the like which exert an influence on the fuel consumption rate but cannot be controlled by driving skills vary according to intervals. Consequently, in evaluation of the driving result in the relatively short time interval, a case may occur such that although driving is efficient, due to relatively bad driving environments, the value of fuel consumption rate is low. On the contrary, a case may occur such that although, driving is inefficient, the driving environments are relatively good, so that the value of fuel consumption rate is high. To properly evaluate the result of driving in a relatively short time interval, it is important to calculate a variable related to the driving environments from interval driving data and make an evaluation in which the driving environments are properly reflected.
Japanese Patent No. 3,314,870 discloses a driving evaluation method capable of making an evaluation of interval driving data in which driving environments are reflected. According to the method, a value obtained by correcting a drive fuel consumption rate by an addition value in which driving environments are reflected is used as an evaluation value of the driving result. However, it is difficult to generate a proper point table for calculating the addition value. In the method, how the driving environments from the interval driving data is estimated is not clarified. Therefore, by this method, actually, it is difficult to make an evaluation of the interval driving data in which the driving environments are reflected.
As another driving evaluation method capable of making an evaluation of interval driving data in which the driving environments are reflected, there is a driving evaluation method in a vehicle-driving-state-evaluating-system disclosed in Japanese Patent Laid-Open No. 2002-362185. In the method, various “driving manners that deteriorate fuel consumption rate” defined on the basis of a domain knowledge of bad driving manners which deteriorate fuel consumption rate are detected from the interval driving data. The difference between actual fuel consumption amount of detected driving and a theoretical fuel consumption amount in the case of ideal driving without driving which deteriorates fuel consumption is calculated, and efficiency of driving is evaluated by the difference. Examples of “driving manners which deteriorate fuel consumption rate” are (1) excessive driving force, (2) over speed, (3) erroneous shifting, (4) racing, and (5) idling. For example, in determination of whether (1) excessive driving force is used or not, by calculating hill climbing resistance at the time of calculating driving force, a driving evaluation in which the driving environment of a hill in a driving road is reflected can be made. The method of detecting “driving manners which deteriorate fuel consumption rate” and evaluating the driving result has an advantage such that inefficient driving can be notified to the driver immediately after detection.
The method, however, has a problem such that since the driving result is evaluated on the basis of detection of pre-defined “driving manners which deteriorate fuel consumption rate”, even if inefficient driving which cannot be detected exists, it is ignored. Moreover, since it is difficult to define a driving manner that deteriorates fuel consumption rate in all of driving environments, even if driving is efficient, it may be evaluated inefficient depending on the driving environments.